Self-tightening clamps, i.e., clamps made from spring wire or spring steel band material, which are also referred to in the art as constant-tension clamps, are known as such. In their simplest form, such clamps, which, by their inherent spring characteristics, normally tend to assume their closed clamping position, consist of spring wire with overlapping, outwardly extending ends, whereby the clamps are opened by forcing the overlapping outwardly extending ends toward one another. Once installed over a hose, the outwardly extending ends are released and the clamp will assume its clamping position. Self-tightening clamps made from band material are also known in the prior art. They usually consist of a tongue-like extension at one end and are preferably provided with a latching device at the other end to latch the clamp in its prestressed condition. The thus-opened latched clamps are shipped to the user who will install the open clamps and then release the latching engagement. The U.S. Pat. Nos. 4,305,791; 4,425,681; 4,773,129; 4,858,279; 4,930,191; 4,930,192 and 4,996,749 are representative of prior art self-tightening clamps made from band material. All of these prior art clamps, however, involve an injury danger in use owing to outwardly extending parts thereof, not to mention lack of clamping surfaces devoid of discontinuities, steps or offsets.
The clamps described in my prior U.S. Pat. No. 5,203,809 represented a significant step in the direction toward greater safety coupled with reliable clamping action over the entire circumference. In particular, the clamp illustrated in FIGS. 24 through 30 has proved commercially successful. However, apart from being relatively complicated and costly to manufacture, its snap-like release from the latched position into the clamping position occasionally produces some sparking which is unacceptable within the area, for example, of gasoline lines and the like. Sparking danger can be reduced with the use of a lacquer cover layer on the surface of the clamp. However, such lacquer layer again increases the cost of the clamp.